The present invention generally relates to a device for measuring the slope of a green on a golf course. More particularly, the present invention relates to a golf putting aid for measuring the slope of a golf course green and providing a golfer with an indication of a lateral offset distance from the hole where the golfer should aim his or her putt so as to compensate for the measured slope of the green.
Many devices have been developed to assist golfers in aligning their putts on sloped greens. In general, these devices provide the golfer with some indication of the degree of slope of the green at the particular location where the device is positioned. Most of these devices utilize a bubble in a liquid-filled tube for this purpose. Such devices may be attached to or physically incorporated in the shaft of a putter. Examples of such devices are disclosed in U.S. Pat. Nos. 4,079,520; 4,179,125; 5,509,657; 5,755,623; and 5,820,476. Alternatively, such leveling devices may be physically incorporated into the head of a putter. Examples of such devices are disclosed in U.S. Pat. Nos. 4,824,114; 5,209,470; 5,492,329; and 5,707,299. The slope measuring devices may also be separate devices that are not attached or incorporated within a putter. Examples of such devices are disclosed in U.S. Pat. Nos. 5,326,096 and 5,403,001.
All of the slope measuring devices described above require that the putter or separate slope measuring device be laid down on the green so as to provide an indication of the relative slope of the green. However, none of the devices described in the above patents informs the golfer where he or she should aim his or her ball relative to the hole so as to compensate for the slope in the green. U.S. Pat. Nos. 4,260,151 and 4,984,791 disclose devices that the golfer holds in his or her hand above the surface of the green so as to look through the device and align it with the slope of the green and the hole. Based upon the alignment of the device, the golfer is provided with some indication as to where to aim when putting so as to compensate for the slope of the green. These devices, however, do not take into account the distance to the cup, which obviously will affect the extent of lateral movement of the ball due to the slope of the green.
To take into account the distance of the putt, devices have been constructed that include a scale for determining the number of inches the ball will break as a result of the slope for various distances of putts. Examples of such devices are disclosed in U.S. Pat. Nos. 4,082,286 and 5,330,179.
While the above-described devices supply the golfer with some information that may be useful to more accurately putt on a green with a constant slope between the ball and the cup, these devices are of little value when the slope varies. For example, even the more sophisticated devices that provide the golfer with the number of inches the ball will break for different distances would not be the least bit accurate or helpful if the green had a non-uniform slope or if it were sloped back the opposite direction somewhere within the line of the putt.